1. Technical Field
The present invention relates generally to spin-on type fluid filters, and more particularly, to a sealing grommet for use in a spin-on type filter.
2. Discussion
The use of sealing grommets in spin-on type filters is well known in the art and may be seen by reference to commonly owned U.S. Pat. No. 5,094,745. Despite the widespread commercial use of such sealing grommets, the prior art sealing grommets are none the less susceptible to improvement.
For example, in many applications it is desirable for the sealing grommet to be received into sealing engagement over a filter adapter standpipe. Due to dimensional variations between the design of the various standpipes, it is frequently necessary to supply a family of spin-on type filters which are identical except for the use of several differently dimensioned sealing grommets. The use of multiple sealing grommets in otherwise similar filters poses several distinct disadvantages. Initially, tooling costs to mold the sealing grommet are substantially increased due to the fact that several molds must be produced. The proliferation of grommet designs substantially increases the risk that the wrong sealing grommet will be used in a filter assembly. Such assembly defects are often not readily discernable due to their similar design and frequently small dimensional differences. The use of multiple sealing grommets also negatively impacts the cost of the filter. Filters which are unique to specific applications due to the size of their sealing grommet are frequently manufactured on low-volume production equipment which is less efficient than the equipment utilized for high-volume filter production. As such, the cost of these grommet-specific filters is negatively impacted by set-up costs as the costs associated with changing over production equipment to fabricate the low-volume filters are amortized over a smaller population of filters as compared to similar high-volume filters. Another consequence of low volume filters is the tendency for the inventory of grommet-specific filters to be consumed at a slower rate, thereby increasing inventory costs relative to the inventory costs for similar high-volume filters. Consequently, there remains a need in the art to produce a sealing grommet for use in a spin-on type fluid filter which can universally adapt to a range of standpipe dimensions.
It is therefore a general object of the present invention to provide a sealing grommet which can sealingly engage standpipes of varying diameters.
It is a more specific object of the present invention to provide a sealing grommet which includes an angled, interior annular flange which sealingly engages a standpipe.
The improved sealing grommet of the present invention includes a generally hollow body portion and an annular flange coupled to an interior wall of the grommet body. The annular flange is configured to sealingly engage the standpipe of a filter adapter. The annular flange depends away from one of the ends of the grommet so as to sealingly engage standpipes of varying diameters. An annular cavity, formed by the interior wall of the grommet body and the annular flange, allows pressurized fluid within the annular cavity to exert forces against the surface of the cavity to thereby enhance the sealing engagement between the filter element, the base plate and the filter adapter standpipe.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.